About 650 people protested a major Walmart distribution center Monday in Elwood, Illinois, the Chicago Tribute reports.

At Walmart contractor Roadlink, workers have been on strike since mid-September, claiming unsafe working conditions and unfair wages. From the movement’s website:

No one should come to work and endure extreme temperatures, inhale dust and chemical residue, and lift thousands of boxes weighing up to 250lbs with no support. Workers never know how long the work day will be- sometimes its two hours, sometimes its 16 hours. Injuries are common, as is discrimination against women and illegal retaliation against workers who speak up for better treatment.

Reports from the protest vary, but photos show riot police restraining some protesters with zip-ties. The rally had apparently been declared an “unlawful assembly.”